Swanand Patil

Size dependency variation in lattice parameter and valency states in nanocrystalline cerium oxide

A correlation between the particle size and the lattice parameter has been established in nanocerium oxide particles (3–30nm). The variation in the lattice parameter is attributed to the lattice strain induced by the introduction of Ce3+ due to the formation of oxygen vacancies. Lattice strain was observed to decrease with an increase in the particle size. Ce3+ ions concentration increased from 17% to 44% with the reduction in the particle size.

Protection from radiation-induced pneumonitis using cerium oxide nanoparticles

In an effort to combat the harmful effects of radiation exposure, we propose that rare-earth cerium oxide (CeO(2)) nanoparticles (free-radical scavengers) protect normal tissue from radiation-induced damage. Preliminary studies suggest that these nanoparticles may be a therapeutic regenerative nanomedicine that will scavenge reactive oxygen species, which are responsible for radiation-induced cell damage. The effectiveness of CeO(2) nanoparticles in radiation protection in murine models during high-dose radiation exposure is investigated, with the ultimate goal of offering a new approach to radiation protection, using nanotechnology. We show that CeO(2) nanoparticles are well tolerated by live animals, and they prevent the onset of radiation-induced pneumonitis when delivered to live animals exposed to high doses of radiation. In the end, these studies provide a tremendous potential for radioprotection and can lead to significant benefits for the preservation of human health and the quality of life for humans receiving radiation therapy.

Role of trivalent La and Nd dopants in lattice distortion and oxygen vacancy generation in cerium oxide nanoparticles

Nanocrystalline Ce1−xRExO2−y (RE=La and Nd) powders were synthesized with a controlled size in the range of 3–5nm using microemulsion technique. The nanoceria retains its cubic fluorite structures for the complete doping range. X-ray diffraction and Raman spectroscopic studies showed that the lattice distortion increased with the doping amount and was found to be higher for La-doped samples compared to the Nd doping. Spatial correlation model used for Raman analysis suggested increased defect concentration for the doped samples compared to nanoceria.

Synthesis of Nanocrystalline Ceria Particles for High Temperature Oxidation Resistant Coating

Cerium oxide has been investigated to be an effective coating material for high temperature applications for various alumina- and chromia-forming alloys. The present study investigates the use of microemulsion method to obtain monodispersed, non-agglomerated nanocrystalline ceria particles in the range of 5 nm using sodium bis(2-ethylhexyl) sulphosuccinate (AOT) as a surfactant. Furthermore, the use of non-agglomerated nanocrystalline ceria particles to develop improved high temperature oxidation resistant coatings on AISI 304-grade stainless steel was investigated. It was found that non-agglomerated nanocrystalline ceria particles were more effective in improving the oxidation resistance than the agglomerated nanocrystalline particles.

Nanoceria Particles Prevent ROI-Induced Blindness

Retinal degeneration caused blindness, such as age-related macular degeneration (AMD), diabetic retinopathy (DR), retinitis pigmentosa (RP) and retinal detachment, is a major problem in clinical ophthalmology. Although genetic modifications are responsible for most retinal degenerative diseases, there is increasing evidence showing that reactive oxygen intermediates (ROIs), the byproducts of the oxidative metabolic reactions, are closely involved in the process of photoreceptor cell degeneration (Beatty et al., 2000; Maeda et al., 2005; Wenzel et al., 2005). These ROIs, including hydrogen peroxide, hypochlorite ions, hydroxyl radicals, hydroxyl ions and superoxide anions (Beatty et al., 2000), react with almost any nearby DNA, RNA, lipid, carbohydrate or protein. They are produced primarily by the normal oxidative metabolism that occurs in the mitochondrial respiratory chain. Photoreceptor cells are extremely sensitive to ROI-induced damage. This is not only because they are continuously exposed to the deleterious effects induced by photons of light, but also they have the highest rate of oxygen metabolism of any cells in the body (Yu and Cringle, 2005) and their outer segments contain high level of polyunsaturated fatty acids. The high consumption of oxygen results in the production of a large amount of ROIs. In consequence, ROIs result in the cytotoxic effect referred to as oxidative stress, which has been implicated as one of the initial causes of numerous eye diseases. It has been shown that, in the retinal degenerative diseases, irrespective of the initiating defect, the intracellular concentration of ROIs rises chronically or acutely and activates a cell death pathway (Lewis et al., 1991; Caldwell et al., 2003; Emerit et al., 2004). Several therapeutic strategies have been tested to treat retinal degeneration in animal models by reducing ROIs (Wenzel et al., 2005). We are introducing a new material, vacancy engineered nanoceria particles, and testing its ability to

Palladium nanoparticle arrays using template-assisted electrodeposition

Palladium nanoparticles are being increasingly considered as room-temperature hydrogen sensors and storage materials. Pd nanoparticle arrays have been synthesized using template-assisted electrodeposition. The template based on Al film on a polymeric substrate was characterized by scanning electron microscopy and energy dispersive spectroscopy. X-ray photoelectron spectroscopy study confirmed that the deposited nanoparticles were of metallic Pd. High-resolution transmission electron microscopy investigation revealed that Pd nanoparticles consisted of a large number of nanocrystallites in the size range of 5–10 nm.

A Novel Nanomaterial Based Electrochemical Sensor for Free Radical Detection

Hydrogen peroxide (H2 O2 ) is not only a product of the reactions catalyzed by a large number of highly selective oxidases but also an essential mediator in food, pharmaceutical and environmental analysis. Therefore its determination is of paramount importance in many areas in chemical, biological and clinical fields. Most H2 O2 biosensors developed till date are based on enzymes and proteins which have a limited sensor life. Moreover, complex procedures are followed for sensor fabrication. Therefore an inorganic material based sensor with a simple design and longer shelf-life is highly desirable. In this work, the development of a novel cerium oxide nanomaterial based electrochemical sensor for the measurement of hydrogen peroxide is described. This has direct ramifications in the development of sensors for other superoxide radicals.Copyright